I know for many who run SBCs (RK3588, Pi, etc.), very little is 1-2W idle, which is almost nothing (and doesn't even need a heatsink if you can stand some throttling from time to time).
Most of the Intel Mini PCs (which are about the same price, with a little more performance) idle at 4-6W, or more.
I don't need to transcode + I need something I can leave on that draws little power.
I have a powerful rig, but the one time I get to turn it off is when I'd need the media server lol.
There's a lot of scenarios where power usage comes into play.
These clusters don't make much sense to me though.